The Center for Basic MR Research at the Radiology Department of Beth Israel Deaconess Medical Center (BIDMC) contains a Bruker BIOSPEC system and a Bruker DRX system. These instruments are currently integrated and are used interactively by a large group of NIH funded investigators, as well as other investigators pursuing pilot studies for future NIH funding. The purpose of this proposal is to upgrade the MRI capabilities of the Center in order to have a state-of-the-art facility for the large number of NIH funded investigators who utilize it. In particular, we are requesting: 1. An upgrade of the BIOSPEC rf electronics from MSL based electronics to Avance based electronics. 2. An upgrade of the rf shielded room of the BIOSPEC to an rf/steel shielded room. 3. An upgrade of the DRX hardware, including an upgrade of the microimaging probe to the micro 2. 5 and the digitizer and phase coherent DDS option. The Avance upgrade will ensure enhanced reliability, signal to noise, and faster imaging capabilities than the current 12 year old MSL electronics. The rf/steel shielded room will enable the magnet to be ramped up to 4.7 T from the present 2 T field strength, increasing the signal to noise and hence resolution of all studies. The micro2.5 probe will replace the original unshielded 10 year old microimaging probe. This new probe will increase gradient switching, imaging speed, and will significantly improve in vivo mouse imaging. Similarly, the upgraded digitizer will enable faster imaging and simpler pulse programming. The proposed upgrade will support 21 projects from 18 investigators at 10 departments in 5 different institutions. 14 projects are currently NIH funded, and 4 others have NIH applications currently under review.